Technical Field
The instant disclosure relates to capacitive sensing technologies, in particular, to a capacitive sensing device and method thereof capable of reducing the influence from transient environmental changes.
Related Art
For the sake of improving convenience of usage, more and more electronic devices adopt touch screens as operating interfaces. A user can touch graphics displayed on a touch screen of an electronic device for manipulating the electronic device. Comparing to button-based manipulations or other manipulation methods, touch-based manipulations are quicker, more convenient, and more ergonomic. The touch screen mainly includes a display device providing a displaying function and a sensing device providing a touching function.
These sensing devices can be classified, according to the structures and the principles applied, into several sensing types, such as resistive sensing, capacitive sensing, acoustic sensing, optic sensing (e.g., infrared ray sensing), and electromagnetic sensing. Specifically, the capacitive sensing devices (i.e., sensing devices belonging to capacitive sensing type) do not require materials having good properties in terms of stress and strain, and are not easily affected by environment light. Furthermore, the manufacturing process of the capacitive sensing devices is simpler than other types of sensing devices. Therefore, most of touch screens which are recently manufactured intend to adopt the capacitive sensing device for the touch-based manipulation.
A conventional capacitive sensing device includes sensing points which are defined by X electrodes and Y electrodes and are configured in an array form. When the user touches the conventional capacitive sensing device, a capacitance value of at least a corresponding sensing point on which the user touches would be changed, and then the conventional capacitive sensing device identifies that a touch manipulation occurs by detecting a variation of the capacitance value of the sensing point. However, when the environment of the conventional capacitive sensing device transiently changes (e.g., temperature change in a short period of time), the capacitive value of the sensing point would increase or decrease according to the environment temperature, such that the conventional capacitive sensing device would misjudge the change of the capacitive value of the sensing point as a touch manipulation.